package com.mylg.craw.house.util;

import com.alibaba.excel.util.StringUtils;

public class DistanceUtils {
    // 地球赤道半径
    private static double EARTH_RADIUS = 6378.137;


    public static Double calculateDistance(String startLnglat, String endLnglat) {
        if (StringUtils.isBlank(startLnglat) || StringUtils.isBlank(endLnglat)) {
            return -1d;
        }
        String[] startLngLat = startLnglat.split(",");
        String[] endLngLat = endLnglat.split(",");
        return getDistance(
                Double.parseDouble(endLngLat[1]),
                Double.parseDouble(endLngLat[0]),
                Double.parseDouble(startLngLat[1]),
                Double.parseDouble(startLngLat[0])
        );
    }

    /**
     * @描述 经纬度获取距离，单位为km
     * @参数 [lat1, lng1, lat2, lng2]
     * @返回值 double
     **/
    public static double getDistance(double lat1, double lng1, double lat2, double lng2) {
        double radLat1 = rad(lat1);
        double radLat2 = rad(lat2);
        double a = radLat1 - radLat2;
        double b = rad(lng1) - rad(lng2);
        double s = 2 * Math.asin(Math.sqrt(Math.pow(Math.sin(a / 2), 2)
                + Math.cos(radLat1) * Math.cos(radLat2)
                * Math.pow(Math.sin(b / 2), 2)));
        s = s * EARTH_RADIUS;
        s = Math.round(s * 10000d) / 10000d;
        return s;
    }

    private static double rad(double d) {
        return d * Math.PI / 180.0;
    }
}
